The figure shows an empty rectangular tank with a capacity of 65 ℓ. The tank has a height of 25 cm. Tap L filled the tank at a rate of 3.1 ℓ per minute. Tap M drained water from the tank at a rate of 1.7 ℓ per minute. Both taps were turned on for 23 minutes and then turned off.
- What is the base area of the tank?
- After both taps were turned off, how much more water is needed to fill the tank completely? Give your answer in litres.
(a)
1 ℓ = 1000 mℓ
65 ℓ = 65 x 1000 = 65000 mℓ
Base area of the tank
=
Volumeheight =
6500025 = 2600 cm
2 (b)
Volume of water that filled the tank per minute when both taps were turned on
= 3.1 - 1.7
= 1.4 ℓ
Volume of water that filled the tank in 23 minutes when both taps were turned on
= 23 x 1.4
= 32.2 ℓ
Volume of water needed to fill the tank
= 65 - 32.2
= 32.8 ℓ
Answer(s): (a) 2600 cm
2; (b) 32.8 ℓ